org.springframework.web.struts
Class ContextLoaderPlugIn

public class ContextLoaderPlugIn

implements PlugIn

Struts 1.1 PlugIn that loads a Spring application context for the Struts ActionServlet. This context will automatically refer to the root WebApplicationContext (loaded by ContextLoaderListener/Servlet) as parent.

The default namespace of the WebApplicationContext is the name of the Struts ActionServlet, suffixed with "-servlet" (e.g. "action-servlet"). The default location of the XmlWebApplicationContext configuration file is therefore "/WEB-INF/action-servlet.xml".

<plug-in className="org.springframework.web.struts.ContextLoaderPlugIn"/>

<plug-in className="org.springframework.web.struts.ContextLoaderPlugIn">
<set-property property="contextConfigLocation" value="/WEB-INF/action-servlet.xml /WEB-INF/myContext.xml"/>
</plug-in>

It is normally preferable to access Spring's root WebApplicationContext in such scenarios, though: A shared middle tier should be defined there rather than in a ContextLoaderPlugin context, for access by any web component. ActionSupport and DispatchActionSupport auto-detect the root context too.

A special usage of this PlugIn is to define Struts Actions themselves as beans, typically wiring them with middle tier components defined in the root context. Such Actions will then be delegated to by proxy definitions in the Struts configuration, using the DelegatingActionProxy class or the DelegatingRequestProcessor.

Note that you can use a single ContextLoaderPlugIn for all Struts modules. That context can in turn be loaded from multiple XML files, for example split according to Struts modules. Alternatively, define one ContextLoaderPlugIn per Struts module, specifying appropriate "contextConfigLocation" parameters.

Note: The idea of delegating to Spring-managed Struts Actions originated in Don Brown's Spring Struts Plugin. ContextLoaderPlugIn and DelegatingActionProxy constitute a clean-room implementation of the same idea, essentially superseding the original plugin. Many thanks to Don Brown and Matt Raible for the original work, and for the agreement to reimplement the idea in standard Spring!

Author:

Juergen Hoeller

Since: 1.0.1

See Also: SERVLET_CONTEXT_PREFIX, ActionSupport, DispatchActionSupport, DelegatingActionProxy, DelegatingRequestProcessor, DelegatingTilesRequestProcessor, ContextLoaderListener, ContextLoaderServlet, FrameworkServlet

public final static Class DEFAULT_CONTEXT_CLASS

Default context class for ContextLoaderPlugIn.

See Also:

XmlWebApplicationContext

public final static String DEFAULT_NAMESPACE_SUFFIX

Suffix for WebApplicationContext namespaces. If a Struts ActionServlet is given the name "action" in a context, the namespace used by this PlugIn will resolve to "action-servlet".

public final static String SERVLET_CONTEXT_PREFIX

Prefix for the ServletContext attribute for the WebApplicationContext. The completion is the Struts module name.

public void destroy()

Close the WebApplicationContext of the ActionServlet.

See Also:

org.springframework.context.ConfigurableApplicationContext.close()

public final ActionServlet getActionServlet()

Return the Struts ActionServlet that this PlugIn is associated with.

public Class getContextClass()

Return the custom context class.

public String getContextConfigLocation()

Return the explicit context config location, if any.

public final ModuleConfig getModuleConfig()

Return the Struts ModuleConfig that this PlugIn is associated with.

public final String getModulePrefix()

Return the prefix of the ModuleConfig that this PlugIn is associated with.

See Also:

org.apache.struts.config.ModuleConfig#getPrefix

public String getNamespace()

Return the namespace for the ActionServlet, falling back to default scheme if no custom namespace was set: e.g. "test-servlet" for a servlet named "test".

public final ServletContext getServletContext()

Return the ServletContext that this PlugIn is associated with.

public String getServletContextAttributeName()

Return the ServletContext attribute name for this PlugIn's WebApplicationContext. Default implementation returns SERVLET_CONTEXT_PREFIX + module prefix.

See Also:

SERVLET_CONTEXT_PREFIX, getModulePrefix()

public final String getServletName()

Return the name of the ActionServlet that this PlugIn is associated with.

public final WebApplicationContext getWebApplicationContext()

Return this PlugIn's WebApplicationContext.

public final void init(ActionServlet actionServlet, ModuleConfig moduleConfig)
                 throws ServletException

Create the ActionServlet's WebApplicationContext.

public void setContextClass(Class contextClass)

Set a custom context class. This class must be of type WebApplicationContext, when using the default ContextLoaderPlugIn implementation, the context class must also implement ConfigurableWebApplicationContext.

See Also:

createWebApplicationContext(org.springframework.web.context.WebApplicationContext)

public void setContextClassName(String contextClassName)
                          throws java.lang.ClassNotFoundException

Set a custom context class by name. This class must be of type WebApplicationContext, when using the default ContextLoaderPlugIn implementation, the context class must also implement ConfigurableWebApplicationContext.

See Also:

createWebApplicationContext(org.springframework.web.context.WebApplicationContext)

public void setContextConfigLocation(String contextConfigLocation)

Set the context config location explicitly, instead of relying on the default location built from the namespace. This location string can consist of multiple locations separated by any number of commas and spaces.

public void setNamespace(String namespace)

Set a custom namespace for the ActionServlet, to be used for building a default context config location.

Association Links

to Class java.lang.String

Suffix for WebApplicationContext namespaces. If a Struts ActionServlet is given the name "action" in a context, the namespace used by this PlugIn will resolve to "action-servlet".

to Class java.lang.Class

Default context class for ContextLoaderPlugIn.

see org.springframework.web.context.support.XmlWebApplicationContext

to Class java.lang.String

Prefix for the ServletContext attribute for the WebApplicationContext. The completion is the Struts module name.

to Class java.lang.Class

Custom WebApplicationContext class

to Class java.lang.String

Namespace for this servlet

to Class java.lang.String

Explicit context config location

to Class org.springframework.web.context.WebApplicationContext

WebApplicationContext for the ActionServlet